Combined treatment of transluminal Nd:YAG laser embolysis and hyperbaric oxygen for branch retinal artery occlusion

Objective: To describe the clinical efficiency of transluminal Nd:YAG laser embolysis (TYE) and hyperbaric oxygen (HBO) as an off-label combined treatment for branch retinal artery occlusion (BRAO) with visible emboli. Methods: A 77-year-old woman had a history of seeing a “shadow” in the lower visual field of the left eye for three days. Platelet-fibrin embolus at the arterial bifurcation was disintegrated by TYE technique and the patient was referred to HBO treatment for 20 sessions. Results: One week after treatment, best-corrected visual acuity improved to 0.8 while a good arterial blood flow in the affected branch was seen. Platelet fibrin plaques had disappeared at fundus, and the pale appearance in the retina had decreased. Conclusions: TYE and HBO combination treatment may be an effective and feasible treatment for restoration of blood flow and vision in BRAO cases caused by visible platelet-fibrin emboli.


Introduction
Case description Branch retinal artery occlusion (BRAO) may result from A 77-year-old woman presented to our clinic complaining obstruction with platelet-fibrin emboli, cholesterol plaques of vision loss for three days in the inferior field of her left or calcific emboli, typically located at the arterial bifurcaeye. She had well-controlled atrial fibrillation and hypertions or areas of narrowing. Patients with BRAO present tension in her systemic history. She also had a history of with sudden loss of vision. Fundus examination usually cataract surgery in both eyes with no complications. In reveals a sectorial superficial whitening and a visible inthe examination, best-corrected visual acuity (BCVA) was tralumenal embolus [1]. BRAO constitutes 38% of all 0.9 in the right eye and 0.3 in the left eye on the Snellen acute retinal artery occlusions [2]. Even though there is scale. Intraocular pressure (IOP) was 14 mm Hg and no definitive treatment for BRAO, a number of treatment 12 mm Hg in the right and left eye respectively, and both options are available, including carbogen inhalation, eyes were pseudophakic. Dilated fundus examination ocular massage, oral acetazolamide and topical antirevealed a superior temporal artery branch occlusion with glaucomatous agents [3]. Opremcak and Benner indicated retinal paleness in the upper region of the macula, with that transluminal Neodyium:yttrium-aluminum-garnet a visible transluminal platelet-fibrin embolus at the arte-(Nd:YAG) laser embolysis (TYE) treatment resulted in imrial bifurcation, and numerous other small fibrin emboli mediate restoration of retinal blood flow and a good scattered along the arterial branch ( Figure 1a). Based on functional recovery [4]. On the other hand, hyperbaric the signs obtained, the diagnosis was confirmed by oxygen (HBO) treatments for retinal artery obstructions fundus fluorescein angiography (FA), visual field (VF) have been performed and yielded favorable outcomes testing (Humphrey 750i Visual Field Analyzer; Carl Zeiss [5]. Meditec, Inc., Dublin, CA, USA) and high definition-optic Due to the visual impairing nature of this condition, an coherence tomography (HD-OCT) (Cirrus HD-OCT; Carl effective emergency treatment capable of reversing the Zeiss Meditec, Dublin, CA, USA). FA showed delayed filling visual loss is needed. Considering prior studies, TYE and of the superotemporal artery and hypofluorescence in HBO as an off-label combined treatment was planned for the surrounding artery ( Figure 1b). HD-OCT revealed difa delayed BRAO case. Herein, we aim to report the clinical fuse thickening of the inner retinal layers and increased efficiency of TYE and HBO combined treatment for BRAO reflectivity (Figure 2a), accompanied by a superior arcuate with visible emboli.
visual field defect in the VF testing ( Figure 3a). Following   pressure over the eye with a contact lens. After the TYE procedure, hyperbaric oxygen treatment was started on the same day and continued for two sessions per day for two weeks, and then reduced to one session per day for a total of 20 sessions. Hyperbaric oxygen was given at 2.4 ATA (atmosphere absolute) pressures for 120 min in each session.
In the follow-up after one week, visual acuity of the patient improved to 0.8. In the fundus examination, no embolic material and hemorrhage was seen, and paleness in the upper temporal field of the macula had decreased (Figure 4a). In the follow-up FA, the normal blood flow was seen in the affected artery (Figure 4b), and the edema was noted to be regressed in the OCT image (Figure 2b). In the fourth week, BCVA was found 0.9. Humphrey 30-2 VF testing showed inferior arcuate scotoma (Figure 3a). The patients's complaint of vision loss has disappeared completely. In the last examination done after 12 months, the patient's visual acuity was 0.9, with inferior nasal quadrant scotoma (Figure 3b), no macular edema on OCT, normal appearance of the fundus and no visible edema.

Discussion
Although a number of treatment options are available for BRAO, one kind of ocular emergency, there is no definitive treatment. Use of other systemic antifibrinolitic agents, intra-arterial fibrinolysis, surgical embolectomy or Nd:Yag laser embolysis (TYE) can be listed as other treatment options [6]. Some studies have reported hyperbaric oxygen as an effective treatment in retinal artery occlusions [5]. TYE has been used in the treatment of both central and branch retinal artery occlusion, and resulted in prompt visual improvement besides capillary reperfusion. Photodisruption of emboli has been found to be related with fast restoration of retinal blood flow and improvement in vision in these patients [4]. In our case, we detected that visual acuity increased by 6 lines (Snellen 0.8) in the first week with combined TYE and HBO treatment, and the blood flow has recovered completely in obstructed arteries in FA. BRAO generally leads to loss of vision with preserved central vision. In our patient, although central retinal involvement was not evident at the beginning, visual acuity was found to be subjectively low due to edema of the retina, older age, and shadowy vision. Retina affected by obstructed artery looks pale because of cloudy swelling that occurs due to intercellular edema, and ophthalmoscopic findings disappear with recovery of blood flow in the artery. Permanent intraretinal layer damage may lead to loss of visual field. It has been stated that a correlation was present between OCT images and histopathologic findings [7]. In our case, edema and pallor, although reduced, were still apparent in the retina field affected in the first month after TYE and HBO. Macular edema was compatible with OCT findings and visual field defect with preserved central vision. Hyperoxia caused by HBO treatment may induce recovery of the retina and macula oxygenation, and restrict fluid leak and edema via vasoconstriction [8]. It has been thought that retinal oxygen treatment can help keep retina cells alive by increasing the retinal oxygen level. In cats, it has been found that 70% oxygen given one day after experimental retinal detachment was highly effective to protect photoreceptors and reduce proliferation [9]. Johannes Menzel-Severing et al. have reported that 3 lines gain in visual acuity were attained after 3-month follow-up in patients who received hyperbaric oxygen treatment and hemodilution treatment together in central retinal artery occlusion, but a gain of one line visual acuity was achieved in the group without oxygen treatment [10]. In our patient, the initial BCVA was 0.3, and it was detected to be 0.8 at one-month follow-up.

Conclusion
The results of our case revealed the satisfactory visual improvement following TYE and HBO treatment in patients with BRAO that have poor initial VA. Even if TYE and HBO combination treatment is an off-label modality, it may be considered in BRAO cases caused by visible platelet-fibrin emboli. It may be a fast, effective and feasible treatment for restoration of blood flow and vision.